FLUOR-PHOTODIODE GAMMA RAY DOSIMETER.
Abstract
A fluor-photodiode gamma ray dosimeter, nicknamed 'Fluorad,' was designed, fabricated, and extensively tested and calibrated. The instrument (sensor head plus recycling circuit) provides output pulses suitable for low sensitivity scaler inputs. The total count (x 10) corresponds to the integrated absorbed dose of a given gamma ray exposure in incremental steps of 10 rads (air) per count. The dosimeter is capable of monitoring both steady state or pulsed radiation fields over an intermediate dose rate range of 10 - 100,000 rads/sec. Energy calibration, using side-by-side dosimetry techniques, was carried out over the range 50 keV to 11 MeV. Various types of ion chambers and thermoluminescent dosimeters were used as the calibrating standards. The measured energy response relative to Co60 over the photon energy range, 100 keV to 10 MeV, was virtually constant. An average absolute sensitivity of 1.5 x 10 to the -8th power C/rad was observed. The measured neutron response at 14 MeV was equal to 0.5 times the first collision dose in standard tissue. Other characteristics measured included: pulsed reactor fission neutron and gamma ray response, linearity of frequency vs. dose rate (or current), directional response, temperature range, saturation and recovery time, spurious pulse rate, and radiation effects. The variations in reproducibility for fixed conditions was less than plus or minus 1%. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 21, 1965
- Accession Number
- AD0641913
Entities
People
- H. S. Katzenstein
- J. Friederichs
- J. Underwood
- M. R. Zatsick
- R. Higa